This invention relates to N-(hydrophobe aromatic)pyridinium compounds and to processes for their preparation and for their use as cationic surfactants, demulsifiers, corrosion inhibitors in acid media.
Pyridinium compounds represented by the formula: ##STR1## wherein R.sup.1 is alkyl such as ethyl and methyl; R.sup.2 is alkyl such as octyl and dodecyl, or aralkyl such as dodecylbenzyl; Z is an anion such as chloride and sulfate; and "a" is 0 or 1, are known to have surfactant activity in aqueous solutions. For example, such surfactants exhibit the following properties: adsorption at interfaces, micelle formation, solubilization of mixtures, reduction of surface and interfacial tension, wetting, foaming and antifoaming, emulsification, dispersion and aggregation, and detergency. These properties enable the surfactants to be used as fabric softeners, antistatic agents, anticoloring agents, herbicides, adhesion promoters, corrosion inhibitors, dispersants, toiletries, flotation aids and germicides.
Such compounds are prepared by reacting a substituted pyridine, e.g., ##STR2## with an organic halide or sulfate, e.g., Z-R.sup.2, wherein R.sup.1, R.sup.2 and Z are as defined before. Under conditions of elevated temperature, these compounds are susceptible to degradation. Thus, their use in the aforementioned applications at high temperatures is severely limited or not considered applicable.
Therefore, it would be highly desirable to provide surfactant compounds having good resistance to thermal degradation in addition to many of the desirable characteristics of conventional pyridinium surfactants.